Question 1

What is Ohm's law?

Accepted Answer

Voltage equals current times resistance: V = I*R.

Question 2

How do I calculate power?

Accepted Answer

Use P = V*I; also P = I^2*R or P = V^2/R for resistive loads.

Question 3

Series vs parallel resistors?

Accepted Answer

Series adds resistances; parallel adds reciprocals. Current and voltage divide differently in each.

Question 4

Can I use this for AC?

Accepted Answer

For basic estimates, yes with RMS values; detailed AC requires complex impedance.

Question 5

What safety margins should I use?

Accepted Answer

Derate components; choose wattage ratings 2x expected dissipation and verify with a multimeter.

Ohm's Law Calculator